Integrated circuits may be formed using various photolithographic techniques. Such techniques typically include use of a chemical mechanical planarization (CMP) process. The CMP process is typically used to grind down and smooth the surface of a semiconductor substrate. In some cases, the CMP process is used to remove some or all of previously formed layer(s) that are no longer needed (i.e. a target layer). The CMP process uses a slurry solution that includes chemicals and solid particles to mechanically and chemically remove the target layer.
The target layer may be, for example, an etch stop hard mask used in a contact hole forming process. With the advance of the technology node and requirements for forming the contact hole with a high aspect ratio, a novel etch stop hard mask including a metal oxide is usually applied. However, it is difficult to remove the etch stop hard mask by the conventional CMP process. Accordingly, a CMP slurry and a method for performing a CMP process using the CMP slurry are required to tackle the problem.